1. Field of the Invention
The invention relates to an electrical connector, and more particularly to a terminal structure of a ZIF (Zero Insertion Force) electrical connector.
2. Description of the Related Art
A center processing unit (CPU) has many pins to be connected to a ZIF (Zero Insertion Force) electrical connector, which is disclosed in Taiwan Patent Publication Nos. 269919 (U.S. Pat. No. 5,616,044), 240866 and 271866.
FIG. 1 is a pictorially exploded view showing a conventional ZIF electrical connector. Referring to FIG. 1, the ZIF electrical connector has a plastic base 10 and several terminals 15. The plastic base 10 is formed with a plurality of terminal slots 11. The terminal 15 has a fixing portion 16, a pin 17, an elastic arm 18 and a contact sheet 19. The fixing portion 16 may be fixed to the terminal slot 11. The pin 17 is connected to the fixing portion 16 and extends downwards. The elastic arm 18 is connected to the fixing portion 16, and the contact sheet 19 is connected to a top of the elastic arm 18. The contact sheet 19 has a two-step shape such that the contact sheet 19 and the terminal slot 11 form a wide region 12 and a narrow region 13 when the terminal is assembled in the terminal slot 11. Thus, when the CPU is connected to the terminal, the pin of the CPU can be inserted into the wide region 12 with zero force, and then slide into the narrow region 13 to be electrically connected to the contact sheet 19.
Although the conventional terminal structure is very simple and easy to be manufactured by way of pressing, the terminal only contacts the pin at a single surface, and the electrical connection effect is not very good.
FIG. 2 is a pictorial view showing a terminal of the conventional ZIF electrical connector, which is disclosed in Taiwan Patent Publication No. 271866. The ZIF electrical connector of FIG. 2 includes an inverse U-shaped main body 21 and a pin 22 connected to a bottom of the main body. The main body 21 is also formed with an inverse U-shaped open slot 23 such that the main body 21 can be elastically opened toward two sides. The open slot 23 is formed with a narrow slot 24. When the CPU is connected to the terminal, the pin of the CPU may be inserted into the front of the narrow slot 24, and then slide into the narrow slot 24 to be electrically connected to the main body 21.
When the pin of the CPU slides into the narrow slot 24 to be electrically connected to the main body 21, the pin of the CPU is clamped by two surfaces, through which the electrical connection is made. However, the connection portions are in the narrow slot 24, which is an open plate slot, and the contact surface areas of the cut surfaces are small because the plate thickness of the main body 21 is small. Thus, the electrical connection effect is not good, and the cut surfaces are rougher and may thus scratch the gold-plated layer of the pin of the CPU.